Vibratory finishing apparatus with a helical and tubular container

ABSTRACT

This invention relates to vibratory finishing apparatus usable for deburring, grinding and polishing workpieces, having a helical and tubular container wound in multi-fold and in multistoried arrangement, said container being connected at each end forming a continuous and endless tube, and having a vibration generating device vibrating said container, workpieces and media, affording spiral and circulatory movements to said workpieces and media.

[451 Nov. 13, 1973 United States Patent [191 Kobayashi 2,760,504 8/1956 Spurlm 198/220 BC 3,618,267 11/1971 51/163 FOREIGN PATENTS OR APPLICATIONS VIBRATORY FINISHING APPARATUS WITH A I-IELICAL AND TUBULAR CONTAINER [76] Inventor:

681,704 10/1952 Great Britain................ 198/220 BC Hisamine Kobayashi, 13,3-chome Kikuzono-cho, Showa-ku, Nagoya, Japan [22] Filed: Apr. 28, 1971 [21] Appl. No.: 138,170

[52] U.S. Cl. 51/163 1 B24b 31/06 [58] Field of 1m. Pieces, having a helical and tubular container Wound 51 /7 1 3; in multi-fold and in multi-storied arrangement, said 198/220 BC container being connected at each end forming a continuous and endless tube, and having a vibration generating device vibrating said container, workpieces and media, affording spiral and circulatory movements to said workpieces and media.

[56] References Cited UNITED STATES PATENTS 2,918,070 12/1959 Carrier 198/220 BC 3,553,900 1/1971 McKibben 51/163 3 Claims, 10 Drawing Figures PATENTEUNUY13 I975 SHEEI 10F 5 F I G. 1

HISAMINE KOBAYASHI INVENTOR \BYZJMAIZ MM ATTORNEY 5 PATENTED NOV 1 3 I973 FIG.2

H ISAMINE KOBAYASHI INVENTOR ATTORNEY s PATENTEDunv 13 I915 SHEET 3 OF 5 FIG.3

HISAMINE KOBAYASHI',

INVENTOR BY fijwlklxl/ ATTORNEY S PATENTEDMUVHIQH 3.771.256 SHEET 50F 5 FIG? HISAM INE KOBAYASHI,

INVENTOR ATTORNEY S VIBRATORY FINISHING APPARATUS WITH A HELICAL AND TUBULAR CONTAINER BACKGROUND OF THE INVENTION The invention relates to barrel finishing, which finishes workpieces with abrasive media by vibrating or rotating a container. In barrel finishing, two kinds of machines have been used; that is, a rotating barrel and a vibratory barrel. This invention relates to a vibratory finishing apparatus. The vibratory barrel finishing machines with box-type or toroidal troughs have a weakness in that finishing and separating are performed independently and discontinuously, that workpieces with complex shapes or relatively long sizes may easily become tangled during the finishing operations, and that indentation marks are easily formed on workpieces of soft metals; and the uses for such machines have been limited.

In a vibratory finishing apparatus with a helical trough connected at the upper and lower ends with a duct, the descending duct is used only for a descending guide for a mass (mixture of workpieces, media, compound and water) and it has no effect for finishing. In

the vibratory finishing machines with a toroidal or helical bowl, the mass is given a spiral motion shifting in the longitudinal direction along the inner wall of the bowl and the workpieces are finished by rubbing with media. However, no helical or longitudinal movement can occur in the descending duct, the mass descends by gravity and no finishing action occurs except due to the natural collision of media and workpieces.

Accordingly, it is an object of the invention to provide a new and improved self-separating vibratory finishing apparatus in which the finishing pressure especially at the descending part is greatly strengthened as compared with the ordinary barrel finishing machine and nearly the same finishing effects can be obtained in both the descending and ascending parts, by a construction in which the tubular container is wound in a multi-fold and multi-storied arrangement, the upper and lower ends of which are connected as an endless tube and by an action in which the mass in the descending part applies pressure to the mass in the ascending part.

It is another object of the invention to provide a vibratory finishing apparatus, which can obtain an effi- V cient volume and length in a relatively narrow space, which, therefore, has high finishing efficiency, which makes the mass flow in good order, which can finish delicate and/or slender workpieces without tangling, which produces no indentation because of uniform flow velocity and which can finish and separate workpieces in one operation. Thus, the invention can provide a new vibratory finishing apparatus fulfilling the demands which cannot be attained by the conventional vibratory finishing.

SUMMARY OF THE INVENTION The invention accomplishes the above and other objects by the provision of a self-separating vibratory finishing apparatus comprising a helical and tubular container wound in multi-fold and in multi-storied arrangement, the upper and lower ends of which are connected for forming an endless tube, charging and discharging openings for the mass and the workpieces into the tubular container, a hollow circular annulus at the center of the helical container, a vibration generating device fixed on the inner wall of the hollow circular annulus, and helical springs supporting the vibrating system. The vibration generating device generates vibration which is transmitted to the tubular container and circulates the mass in the tubular container with appropriate pressure and circulating power. Thus, the workpieces are adequately finished.

Included in the objects of this invention are:

First; to provide a vibratory finishing apparatus for finishing workpieces not only in the ascending part but in the descending part of the tubular container. Second, to provide a vibratory finishing apparatus for finishing workpieces without tangling when an adequate tube diameter is selected. Third, to provide a vibratory finishing apparatus for increasing the effective volume in a relatively narrow space. Fourth, to provide a vibratory finishing apparatus for eliminating the indentations on the workpiece surfaces by making the mass flow uniform in all the tubular container. Fifth, to provide a vibratory finishing apparatus for finishing and separating the workpieces in a continuous operation. Sixth, to provide a vibratory finishing apparatus for selecting'the optimum finishing time and finishing distance in choosing the number of times of the circulation of the mass, in the tubular container. Seventh, to provide a vibratory finishing apparatus for providing the optimum finishing action to the workpieces in choosing the mass route either from the inner to the outer tube or from the outer to the inner tube according to the object being finished.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side elevational view of a vibratory finishing apparatus constructed in accordance with the principles of the invention with certain components illustrated in phantom line.

FIG. 2 is a plan view of the apparatus shown in FIG. 1.

FIG. 3-is a vertical sectional view of the uppermost story shown in FIG. 2 with the section taken alone the line LL.

FIG. 4 and FIG. 5 are the views similar to FIG. 3, but show another embodiment for selecting apparatus for one directional movement of the mass.

FIG. 6 shows another embodiment of the invention which is a four-fold and five-storied vibratory finishing apparatus.

FIG. 7 is a plan view of FIG. 6.

FIG. 8 and FIG. 9 are the sectional views of the container showing the flowing condition of the mass.

FIG. 10 shows the condition of the circulating mass in a trough for a conventional vibratory finishing apparatus with toroidal or helical trough.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1 and FIG. 6, a finishing apparatus is shown as including a helical and tubular convtainer wound in a multi-fold and multi-storied arrangement, the diameter of the container being much smaller than the known toroidal or helical trough, the length of the container being ten to several tens times longer than that of the conventional toroidal or helical vibratory finishing trough. Th surface area of the inner wall of the container which delivers the vibration to the mass is much increased, the distance the mass is moved helically is increased as much as several tens to several hundreds time, the mass in the descending part applies pressure to the mass in the ascending part, and, therefore, the finishing efficiency is greatly increased and the finishing time is reduced to about a half of that of the conventional vibratory finishing apparatus. The size of the diameter of the uniform tubular container with the multi-fold and multi-storied arrangement should be determined by the size of workpieces. For instance, when knives and forks of about 200mm length are finished, a suitable diameter of the container is about 150mm which is smaller than the length of the workpieces. In choosing such size, the blockage of the container by the workpieces and the tangling of the workpieces may be avoided. Accordingly, since the workpieces slide in the tubular container separately, the workpieces with complex shapes can be finished without tangling in the finishing operation and workpieces of soft metals and alloys can be finished without any indentation, thus developing a new field of finishing. Except in the vibratory finishing machine according to the invention, such workpieces cannot be finished.

Referring now to FIG. 1 and FIG. 2, the intermediate part of a uniform tube of small diameter is bent like a ring as shown in A of FIG. 2 constituting the lowest part of the container, and both sides of the tube 1 and 2 are wound up in a multi-fold and multi-storied arrangement as shown in 1a, 1b, 1c and 2a, 2b, 20. Both ends of the tube 1c and 2c are connected as shown in B at the uppermost story, to form a helical and continuous tubular container, on the upper part of each of which is provided charging opening for the mass 6, 7 and the lower part of which is provided with discharging opening for the mass 34, said tubular container being fixed by a hollow circular annulus 8 and ribs 9 and fixed on flange 10. The whole system is suspended on helical springs 12 fixed at one end to the top of a pedestal 11 and disposed at substantially equal angular intervals. At the lower portion of the interior of said annulus 8 is provided a vibration generating unit, consisting of an electric motor and eccentric weights 35, 36, 37 and 38 on both ends ofa vertical shaft.

As shown in FIG. 3, a separation unit is fixedly secured on the top of the container. Said separation unit includes a barrier 14 fixed at the tube bottom, rotative flaps l5, l6, sieve 17, 18, sieve frame 19, 20 and a cover 21. The vibration generating device 13 is energized to forcedly vibrate the container to impart a motion to the mass 25 including the media and workpieces filled into the tubular container from the charging openings 6, 7. The vibratory motion has two components, one of which causes the mass to move in an orbital path as shown by the arrows 25, 25a and the other of which causes the mass to travel linearly in a direction reverse to the direction of the rotation of the motor. Accordingly, for a separation unit available for both directions of the mass flow as shown in FIG. 2, a reversible motor must be used and the direction of rotation of the motor is reversed. For instance, when the mass is moved anticlockwise, mass moves along the outer tube 2b from the charging opening 6 as shown by an arrow 26 in FIG. 2, continuous to move downwards to 2a, 2 and finally arrives in inner container 1 passingthrough A. From the inner container 1, the mass moves upwards to 20 passing la, 1b and as shown by an arrow 26a, and continues to move to the separation unit as shown by an arrow 27 indicated in FIG. 3. In this case, one of the flaps 15 is dispsosed on the barrier 14 and the other flap 16 is lifted as shown at 16a in FIG. 3, and therefore, the mass slides on the flap l5, reachss the sieve 17, drops the chips through the screen into the upper part of the helical container and the workpieces are discharged to the outside of the apparatus as shown by an arrow 33.

Abrasive media 32b dropped through the sieve 18 pass through the connecting tube B, mixed with unfinished workpieces put in from the charging opening 7, re-circulate as shown by an arrow indicated by broken line and finish the workpieces continuously. It is preferable to change the sieve 18 or 17 to a rubber plate (not indicated in the figure) when the path of the mass as indicated at 28 or 32, respectively, in order to prevent a the abrasive media on the barrier and in front of the barrier from creeping out on the sieve 18.

Now, reference is directed to FIG. 6 and FIG. 7 which show a four-fold and five-storied tubular container. The construction is similar to that of FIG. 1 and FIG. 2. The middle part of a long tube is bent as shown A for forming a ring and the lowest part of the con tainer, one side of the tube is wound up as shown by 1,, 1 a, 1 b, 1 c, 1 d, 1 c for forming a five-storied innermost tube, the other side of the tube is wound up outside of the innermost tube as shown by 2 a, 2,b, 2 c, 2,e for forming a five-storied tube, from the upper part of 2,e the tube is again wound down outside of the tube 2 as shown by 8,, 3a, 3b, 3c, 3d, 3e also for forming a five-storied tube, from the end of which, the tube is again wound up outside of the tube 3 as shown by A 4a, 4b, 4c, 4d, 4e and connected to l,e through an upper connecting tube B on the whole, for forming an endless, closed, four-fold and five-storied tubular'container. On the upper part of the tubular container, charging openings 6a, 7a and a separation unit 5a are disposed and on the lower part of the tubular container, charging opening 34a is disposed. The tubular container is fixed on a flange 10a by a hollow circular annulus 8, and ribs 94. The whole system is suspended on helical springs 12; fixed at one end to the top of a pedestal 11a and disposed at substantially equal angular intervals. At the lower portion of the interior of said annulus 8 is provided a vibration generating unit, constituted of electric motor 13 and eccentric weights 35, 36, 37 and 38 on both ends of a vertical shaft. It is preferable that the multi-fold and multi-storied tubular container be an even-fold one, that the innermost and outmost tubular containers constitute the last and upward path for the media. The odd-fold construction which connects the upper and lower part of the innermost and outermost tubular container is unstable in its action. With such a construction, in one direction of the rotation of the motor, the volume of the container holding a descending mass becomes greater than that for the ascending mass and the container for the descending mass at the final stage of finishing has no corresponding ascending mass which prevents the mass from free falling. Therefore, the mass falls freely at the final stage and the objects and media collide with each other. The odd-fold construction, thus, must be avoided. However, both odd and even-storied constructions may be used. Regarding to the designing practice, it must be considered that the upper connecting tube must be easily attached and that the whole construction be balanced. The cross-section is preferably circular, but it may be O-shaped which is circular at both upper and lower ends and vertical at the sides. The material of the tubular container may be metallic with rubber lining, wear resistant synthetic plastic, with a rubber flange or metallic connector or other materials which can resist vibration and finishing action.

For the emboidment of the invention, as indicated in FIG. 1, the outer and inner parts of the tubular container are separated by fixing frame 23 and a hollow circular annulus 8, and upper and lower parts of the tubular container are fixed by fixtures 22, 22a, 22b and 220. In the embodiment of FIG. 6, the fixing method is similar to that of FIG. 1, and any fixing method can be adopted if the function and strength for multi-fold and multi-storied construction are maintained.

In the embodiment of FIG. 6 and FIG. 7, the flowing path of the mass is similar to that of FIG. 1 and FIG. 2. In the case of the counterclockwise flow direction of the mass, the mass is charged from the charging opening 6a or from both charging openings 6a and 7,a simultaneously, and is delivered to the outermost part 4d as shown by an arrow 26a. Then, the mass descends to inner part 3e passing through A and 26b, moves upwards to 2,e passing through 3e, 3d,-3'c, 3b, 3a, 3 and upper connecting tube B as shown by an arrow 260 in FIG. 7, descends again to the innermost part 1 passing through 2,a, 2, and lower connecting part A as shown by 26d, ascends to 1,2 through l,a, is transported to the separation unit 5a passing through the upper connecting tube B as shown by an arrow 262 in FIG. 7 and is finally separated. In the case of the clockwise direction of the mass flow, the mass is delivered to the innermost part l,e as shown by a dotted arrow 30a, descends to 1 a, is fed to the inner part 2 through A as shown by a dotted arrow 30b, ascends to 2,e through 2,11, is fed to the inner part 3 through B as shown by a dotted arrow 30c, descends to 4 through 3a, 32 and A as shown by a dotted arrow 30d, is delivered to the separation unit and is finally separated. In the embodiment of FIG. 6 and FIG. 7, the'mass is charged into the tubular container from charging opening 7a, or from 7a and 7,a simultaneously and the tubular container is filled with the mass. For the separation unit, a two directional separation unit as shown by FIG. 3 ora one directional separation unit can be used as shown by FIG. 4 and FIG. 5 as in the case of a two-fold and three-storied tubular container. For one directional separation, barrier 14a and 145 shown in FIG. 4 and FIG. 5 can deliver the mass on the sieve 17a and 17b without the aid of any other attachments, for instance, rotary flap, flow regulating dam or the like. However, these attachments can aid the mass in ascending to the sieve, and these attachments are also in the scope of the invention. Small discharge openings 39, 40, 41 and 42 are also disposed on the vibratory finishing apparatus. Thesesmall discharge openings are used in order to discharge the excess abrasive media after all workpieces are charged.

In the operation of the vibratory finishing apparatus according to the invention, the finishing is performed in a long path continuously to permit the mass to take a helical motion along the inner periphery of the tubular container with upward and downward motions under heavy pressure. It is necessary to fill ample mass into the tubular container in order to finish the workpieces satisfactorily with the vibratory finishing apparatus. The volume of the mass which is necessary is about 95 per cent of the total container volume. It order to fill the mass into the tubular container, it is necessary to charge abrasive media from the charging openings which are opened on the downward parts of the container, to vibrate the mass and container at 900 to 1,200 cycles per minute, to push up the media to all upward parts of the tubular contain and to fill the rest of the whole tubular container with media. For instance, with the two-fold and three-storied tubular container shown in FIG. 3 or with the four-fold and five-storied tubular container shown in FIG. 7, charging openings 6, 7 or 6a, 7a are disposed on the upper parts of the innermost and outermost parts of the tubular container. Another charging opening is disposed on the upper connecting tube (for instance, 7 a on B shown in FIG. 7) between the ascending and descending parts of the tubular container in order to use the opening last mentioned for both directions of the mass flow. When the direction of the mass flow is counterclockwise, the mass is charged from the charging opening 6 or 6a, or charged from the charging openings 6a and 7a, simultaneously. When the direction of the mass flow is clockwise, the mass is charged from the charging opening 7 or 7a, or charged from the charging openings 7a and 7 a, simultaneously.

As above-mentioned, it is desirable to dispose the charging opening as described, that is, the charging openings are disposed on the upper parts of the innermost and outermost part of the tubular container and the other charging opening which is common for both flow directions of the mass is disposed on the connecting tube between the outermost and innermost parts of the tubular container. Thus, four and five charging openings are provided in a six-fold and eight-fold tubular container, respectively. The abrasive media are charged in the tubular container simultaneously from the necessary charging openings as above described, and the tubular container is filled uniformly with said abrasive media. The abrasive media may be charged from one charging port, but it takes a long time to fill the tubular container with media. It is efficient to charge the media from many charging openings.

After the abrasive media are charged into the tubular container and the vibrating cycle is increasedto at a minimum 1,500 or to at a maximum 2,400 cycles per minute, the workpieces are put into the tubular container from each charging opening and are finished. The rate of the vibrations is ordinarily from 1,500 to 1,800 cycles per minute, but may be increased to 2,400 cycles per minute in accordance with the objects being finished. Since the tubular container is filled with abrasive media when theworkpieces are charged, the mass flows steadily, the workpieces of complex shapes can be finished without tangling and without indention. As the volume of the workpieces mixed into the mass is predetermined, the volume of the whole mass in the tubular container must be adjusted by extracting the excess abrasive media from said small discharging opening 39, 40a or 41, 42a, successively, during the times the workpieces are charged.

After charging the predetermined volume of the workpieces, the workpieces are continuously charged at a definite time interval. Thus, the workpieces are finished and separated continuously during one circulation.'The period of the circulation can be adjusted by the phase difference of the upper and lower eccentric weight fixed on both ends of the motor shaft, in the range of 1:4 for minimum and maximum circulation periods. From the experiments, the workpieces can be finish in to 40 minutes by the apparatus. Therefore, the length of the tubular container is determined so that the period of the mass circulation is 10 to 40 minutes when the apparatus is used for a continuous finishing and separating processes. However, a shorter tubular container can be used when the workpieces are finished in a definite time and the separating operation is commenced by closing the path by one of the flaps and 16 as shown at the position 15 and 16 in FIG. 3. This invention relates to a vibratory finishing apparatus having a helical and tubular container wound in a multi-fold and in multi-storied arrangement with a vibration generating device which vibrates the container with the mass so that the mass both in the inner and outer parts of the tubular container can be circulated in a similar helical path and the workpieces can be finished under pressure. According to the invention, the mass is filled into a tubular container with a multi-fold and multi-storied arrangement, the mass is circulated helically along the periphery of the tubular container by vibrating the container and the mass, and the workpieces are finished under pressure not only in the ascending part but also in the descending part of the tubular container. According to the invention, the total length of the tubular container is greatly increased as compared with the conventional vibratory finishing apparatus, the surface area of the inner wall of the tubular container is very wide and high finishing efficiency can be obtained with a relatively small apparatus. Accord- TABLE 1.FINISIIING CONDITION Finishing condition (1) (2) (3) Apparatus:

Name 01' 'lornidnl Vihi'tt- Helical and Tubular vibraapparetus. tory finishing toroidal vitory finishing apparatus brzttory ilnwith multiwith circular ishing nppafold and mulbottom. ratus witi tlstoricd circular arrangement. bottom. Form of Horizontal Two-fold Two-told and trough. bottom. three-storied (as shown in Figure 1). Trade name OL-300 CCL-O OWE-300. Capacity 300 liters 300 liters 300 liters. Manufactur- Shikishima Shikishirna Shikishima ing com- Tipton Mfg Tipton Mfg 'Iipton Mig pany. 0. Ltd. Co. Ltd. Co. Ltd. Vibraltmg 1,800 oycle/min.. 1,800 cycle/min" 1,800 cycle/min.

eye 8. Amplitude. 6 mm 6 mm 6 mm Relative ad- 30 9 60.

vance angle of the upper weight. Number of 17 12 84 helical circulation.

Abrasive media. Example of ox- The same The same.

pcriments (1) (2) (3) (IS-5. Example of ex periments (4) (5) (6) 08-2.

Compound Example of cx- The same The same.

pcriments (1) (2) (3) CLU- 750. Example of expcriments (4) 700.

TABLE 2.--EXPERIMENTAL RESULTS Finish- Number Flllihlling Stock Ratio of Number oi oi expcrling (-.ontime, removal stock tan led Indentation Name of workpieces merits (lition min (mg) removal wor pieces and bend Automobile part (back-mirror stay) (1) 1 30 33. 0 1.00 0.-. 18% (18 pieces). Zinc die-cast part, 137.2 g./p1 eee. (2) 2 40. 5 0.80 0. 18% (11 pieces). Piece of 167 mm. long, 100 pieces (3) 3 15 42. 4 2. 51 0... Fork (4) 1 40 18. 5 1.00 47% (282 pieces). 27.2% (164 pieces). Part of stainless steel, 37.3 g. (5) 2 20. 7 0.89 18% (109 pieces)- 9.6% (58 pieces). Piece of 200 mm. long, 600 pieces... (6) 3 20 24. 1 3.60 0 0.

ing to the invention, relatively long workpieces such as knives and forks can be finished without becoming tangled by selecting a proper diameter of the tubular container. The vibration mode of the inner and outer parts of the tubular container is naturally different because the tubular container is in a multi-fold arrangement and is vibrated by one vibration generating device. However, proper finishing can be obtained by using either of the two directions of the mass flow by using a reversible motor. According to the invention, the workpieces As can be seen from the experiments, the finishing apparatus according to the invention has a much higher finishing efficiency as compared with the conventional vibratory finishing apparatus. This is due to the fact that the finishing apparatus according to the invention finishes the workpieces under higher pressure as compared with the conventional apparatus. The vibratory finishing apparatus used in the finishing condition (1) listed in TABLE 1 and TABLE 2 is a conventional one with a horizontal and toroidal trough, and the apparatus used in the finishing condition (2) is also a conventional one with helical and toroidal trough, in which much vibratory energy is consumed to cause the mass to flow upwards, resulting in lower finishing efficiency as compared with the condition (1 The causes of lower finishing efficiency for the finishing condition (2) can be explained by the large advance angle of the upper eccentric weights relative to the lower one, both of which are fixed at both ends of the motor shaft. Calculation can show that a large advanceangle causes a large inclination of the vertical axis of the trough and the result is to increase the horizontal component of movement of the mass. A horizontal component of movement causes the longitudinal mass to flow, but, has less effect in finishing. Since in the experimental conditions in (l) and (2), the advance angles are 30 and 90, respectively, the condition (2) has lower finishing efficiency. However, the vibratory finishing machine according to the invention has an advance angle of 60 as shown in TABLE 1, the angle being too small to cause the mass to flow upwards in the conventional helical vibratory finishing apparatus. That is to say, with such an advance angle of the eccentric weights the conventional machine cannot cause the mass to flow upwards, while the vibratory finishing machine according to the invention can cause the mass to flow upwards by the aid of lifting pressure caused by the pressure of the mass circulating downwards. Accordingly, the ascending mass is forced to circulate due to its receiving higher pressure than that with the conventional vibratory finishing machine. In the conventional vibratory finishing machine, the falling mass has no finishing effect ordinarily because the mass fals down in a passage with rapid velocity, but in the vibratory finishing apparatus according to the invention the descending mass has nearly the same finishing efficiency as compared with the ascending mass because the descending mass is blocked by the ascending mass, pushes up the ascending mass by applying an ascending force and the ascending mass receives the pressure from the descending mass to circulate along the periphery of the tubular container.

The advance angle listed in the condition (3) is selected according to the experiment listed in TABLE 1 and TABLE 2, but the value of the advance angle must be selected in considering the weight, dimensions, position of the center of gracity of the vibrating system, position of the motor and unbalanced forces caused by eccentric weights. An advance angle by which one of the upper weights leads the other weight should be generally greater than zero but smaller than 180.

Causes of higher efficiency of the vibratory finishing apparatus according to the invention can be explained.

by using FIGS. 8, 9 and 10. FIGS. 8 and 9 show crosssections of the tubular container according to the invention, showing that the container includes mass in more than 90 per cent of the whole volume, and FIG. 10 shows a cross-section of the toroidal trough of the conventional type, showing that the trough contains mass in an amount of about 80 per cent of the whole volume. Referring to FIGS. 8, 9 and 10, when the amplitude and frequency of vibration is the same in FIGS. 8 and 10, the effective mass which has finishing action in the apparatus according to the invention is about 75 per cent of the whole mass as shown by I in FIG. 8 and the non-effective mass which falls down by gravity is less than 25 per cent as shwon by II in FIG. 8. In the conventional vibratory finishing apparatus, the effec- 1 tive mass I is about 35 per cent of the whole mass and the non-effective mass [I is about 65 per cent as shown in FIG. 10. Therefore, the effective mass in FIG. 8 and FIG. 10 is 0.90 X 0.75 0.67 and 0.80 X 0.35 0.28respectively. That means that the former has 2.4 times higher finishing efficiency, and this is the same order of multiple indicated in TABLE 2.

When the frequency is increased to 1,800 cycles per minute or to more than 2,000 cycles per minute, the whole mass is circulated along the periphery of the tubular container as shown in FIG. 9 and the effective mass attains per cent. In the vibratory finishing apparatus of the invention, difi'erent finishing effects are obtained in accordance with the charging position of the workpieces. In the outer part, the amplitude is greater than that in the inner part, that is, the outer part has higher finishing efficiency than the inner part. When the workpieces are charged from the outer part and discharged from the inner part of the tubular con-- tainer, the rough finishing is firstly performed in the outer descending part and fine finishing is secondly performed in the inner part and in this case alundum or ceramic media are preferably used. When the workpieces are charged from the inner part and discharged form the outer part of the tubular container, deburring is firstly performed in the inner part and heavy finishing is secondly performed in the outer part and in this case plate-like or pellet-type media for heavy finishing made from alundum or silicon carbide are used, metallic or plasticmedia also being usable. The charging position may be thus selected depending on the object and condition of finishing.

According to the invention, the workpieces can be finished under high pressure both in ascending and descending parts of the helical tubular container, vibrating energy can be reduced because the descending mass can put pressure upon the ascending mass and effective finishing action can be obtained in the descending mass as well as in the ascending mass. Relatively long and/or delicate workpieces can be finished in a relatively small space, continuous finishing can be performed under a condition in which the finishing can be completed in one circulation of the mass in the helical container, and higher finishing efficiency can be obtained as compared with the conventional vibratory finishing devices.

I claim:

l. A vibratory finishing apparatus for finishing the surface of workpieces comprising:

a. a closed tubular container wound around a central space in a multi-fold and multi-storied arrangement and a closed connecting tube of nearly the same diameter as said tubular container connecting both ends of said tubular containerfor forming a closed helical and endless tube;

b. a vibration generating motor operatively associated with said tubular container with the motor shaft on the axis of said central space and having eccentric weights thereon for subjecting a mixture comprising said abrasive media and said workpieces to vibration for moving them in a closed path around the axis of said helical and endless tube to cause finishing of said workpieces and to cause said mixture to travel along said tubular container;

c. said container having only charging openings for charging said workpieces and media and discharging openings for discharging said workpieces and said media, a portion of said discharging openings having sieve means thereover and said helical and endless tube having flaps therein adjacent said sieve means and movable to inclined positions in said tubular container for blocking flow of workpieces and media and causing them to flow up the flaps onto said sieve means where the media flows through the sieve means back into the tubular container to thereby be separated from the workpieces; and

3. A vibratory finishing apparatus as claimed in claim 1 in which said tubular container has a small diameter and is wound in a four-fold and five-storied arrangement and said vibration generating device is reversibly rotatable. 

1. A vibratory finishing apparatus for finishing the surface of workpieces comprising: a. a closed tubular container wound around a central space in a multi-fold and multi-storied arrangement and a closed connecting tube of nearly the same diameter as said tubular container connecting both ends of said tubular container for forming a closed helical and endless tube; b. a vibration generating motor operatively associated with said tubular container with the motor shaft on the axis of said central space and having eccentric weights thereon for subjecting a mixture comprising said abrasive media and said workpieces to vibration for moving them in a closed path around the axis of said helical and endless tube to cause finishing of said workpieces and to cause said mixture to travel along said tubular container; c. said container having only charging openings for charging said workpieces and media and discharging openings for discharging said workpieces and said media, a portion of said discharging openings having sieve means thereover and said helical and endless tube having flaps therein adjacent said sieve means and movable to inclined positions in said tubular container for blocking flow of workpieces and media and causing them to flow up the flaps onto said sieve means where the media flows through the sieve means back into the tubular container to thereby be separated from the workpieces; and d. means resiliently supporting said tubular container.
 2. A vibratory finishing apparatus as claimed in claim 1 in which said tubular container is wound in a two-fold and three-storied arrangement and said vibration generating means is reversibly rotatable.
 3. A vibratory finishing apparatus as claimed in claim 1 in which said tubular container has a small diameter and is wound in a four-fold and five-storied arrangement and said vibration generating device is reversibly rotatable. 